package cn.rocky.offer;

public class offer28 {

    public class TreeNode {
        int val;
        TreeNode left;
        TreeNode right;

        TreeNode(int x) {
            val = x;
        }
    }
    public boolean isSymmetric(TreeNode root) {
        return root == null ? true : recur(root.left, root.right);
    }

    boolean recur(TreeNode L,TreeNode R) {
        if (L == null && R == null) {
            return true;
        }
        if (L == null || R == null || L.val != R.val) {
            return false;
        }
        return recur(L.left,R.right) && recur(L.right,R.left);
    }
}
